octa-

例句：

1. 1.The octave of the piano is where the highest notes are played.
   钢琴的八度是演奏最高音符的地方。
2. 2. The octave scale is a key part of music theory.
   八度音阶是音乐理论的关键部分。
3. 3. Octaves are used to create complex harmonies in music.
   八度用于在音乐中创建复杂的和声。